I18n.hs: Implement custom i18n using Haskell data types

Follow the example
https://wiki.haskell.org/Internationalization_of_Haskell_programs_using_Haskell_data_types
to get i18n.

Get rid of the Shakespeare-I18N code. The idea of using text files to
define translation strings was nice, but since I couldn't get it working
with ease and couldn't find examples outside of a Yesod context, I
decided to chuck it and go with the alternative, simpler approach.

Really liking this system. Simplified things a bit from the example
since we only need to show one language at a time. Will need to figure
out how to use the same language throughout the program.

2 files changed, 12 insertions, 19 deletions

diff --git a/src/I18n.hs b/src/I18n.hs
index 988c823..5a74d80 100644
--- a/src/I18n.hs
+++ b/src/I18n.hs
@@ -1,30 +1,25 @@
-{-# LANGUAGE FlexibleContexts #-}
-{-# LANGUAGE MultiParamTypeClasses #-}
 {-# LANGUAGE OverloadedStrings #-}
-{-# LANGUAGE TemplateHaskell #-}
 
 module I18n
     ( Locale(..)
-    , RenderMessage
+    , Message(..)
 
-    , mkMessage
     , translate
     ) where
 
 import qualified Data.Text as T
 
-import Text.Shakespeare.I18N (mkMessage, renderMessage, RenderMessage)
-
-data Bot = Bot
-
 data Locale = EN | FR
 
-toISOLocale :: Locale -> T.Text
-toISOLocale EN = "en"
-toISOLocale FR = "fr"
+data Message
+    = GitHubCommitRepoURLNotFound
+    | GitRemoteSetOriginUpdatedRepoURL T.Text
 
-mkMessage "Bot" "messages" "en"
+translate_en_US :: Message -> T.Text
+translate_en_US GitHubCommitRepoURLNotFound = "I couldn't find a repo URL for \
+    \this channel. Try `git remote set origin REPO_URL`."
+translate_en_US (GitRemoteSetOriginUpdatedRepoURL url) =
+    "I updated the channel's repo URL to '" `T.append` url `T.append` "'."
 
-translate :: (RenderMessage Bot b) => Locale -> b -> T.Text
-translate locale message =
-    renderMessage Bot [(toISOLocale locale)] message
+translate :: Locale -> Message -> T.Text
+translate EN = translate_en_US
diff --git a/src/Plugin/GitHubCommit.hs b/src/Plugin/GitHubCommit.hs
index 23de2fa..8b43b57 100644
--- a/src/Plugin/GitHubCommit.hs
+++ b/src/Plugin/GitHubCommit.hs
@@ -33,9 +33,7 @@ gitHubCommitAction message = do
     return $ respond rs
   where
     respond [] =
-        -- Left "I couldn't find a repo URL for this channel. \
-        --     \Try `git remote set origin REPO_URL`."
-        Left $ translate EN MsgGitHubCommitRepoURLNotFound
+        Left $ translate EN GitHubCommitRepoURLNotFound
     respond ((RepoUrlRow r):_) =
         Right $ r `T.append` "/commits/" `T.append` T.pack (
             M.textStr message =~ matchRegex gitHubCommit)